---
schema_version: "secwatch.filing_event.v1"
accession: "0001447362-22-000016"
form_type: "8-K/A"
ticker: "CSTL"
cik: "0001447362"
company_name: "CASTLE BIOSCIENCES INC"
filed_at: "2022-01-14T23:59:59+00:00"
generated_at: "2026-06-27T17:53:56.938151+00:00"
event_type: "m_and_a"
sentiment: "positive"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# Castle Biosciences acquires Cernostics for up to $30M upfront plus $50M earnout

## Summary
- Up-front consideration $30M (cash or cash/stock mix); earnouts up to $50M based on 2022 commercial milestones.
- Cernostics 9M2021 revenue $469K, net loss $2.8M; 2020 revenue $141K, net loss $2.6M.
- Cernostics' TissueCypher Barrett's Esophagus Assay added to Castle's diagnostics portfolio.
- Transaction closed December 2021; amendment files required financial statements.

## SEC filing metadata
- accession: 0001447362-22-000016
- form_type: 8-K/A
- ticker: CSTL
- cik: 0001447362
- company_name: CASTLE BIOSCIENCES INC
- filed_at: 2022-01-14T23:59:59+00:00
- event_type: m_and_a
- sentiment: positive
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1447362/000144736222000016/0001447362-22-000016-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1447362/000144736222000016/cstl-20211202.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001447362-22-000016
- JSON: https://secwatch.observer/filing/0001447362-22-000016.json
- Plain text: https://secwatch.observer/filing/0001447362-22-000016.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.